Taking a different view.
Its obvious that when the building was built, there was a common antenna and tv outlets to every lot.
Its certain thst the antenna and the distribution box is common property. It can be argued thst from the distribution box to the tv outlet in each unit, the cable is also common property. (As it’s usually in the common property walls.
Therefore, the owners corporation has the duty to maintain common property, hence the OC obliged to fix the tv system. It doesn’t matter whether some or none of the lots use it( the analogy is a lift in a building where some lots do not need to use a lift , but still pay for it’s upkeep).
We all know older buildings need from time to time an upgrade of infrastructure. This is such a case.
If the OC doesn’t want to go the upgrade route, and you want it, a visit to NCAT may be necessary for an adjudication.